Gallery: Crackdown in south Philippines

Thousands of troops in tanks and warplanes have taken control of the southern province of Maguindanao, after Gloria Macapagal Arroyo, the Philippine president, declared martial law in the area [EPA]

The drastic move, imposed for the first time in nearly 30 years anywhere in the country, came as security forces clashed with armed men loyal to a powerful local political family [Reuters]

Andal Ampatuan Sr, the provincial governor and head of the Ampatuan clan, was detained shortly after martial law was declared accused of orchestrating an election-related massacre of 57 activists and journalists [AFP]

His son Andal Ampatuan Jr, the main suspect, already faces multiple counts of murder for the November 23 incident, described as the Philippines' worst-ever politically-related killings [EPA]

The government says more than 3,000 armed men loyal to the Ampatuans remain a security threat across the province [Reuters]

Security forces sealed off Maguindanao's exit points and mounted checkpoints amid fears that the gunmen could carry out further attacks [EPA]

The Philippines military has shown firearms, crates of ammunition and mortar shells they say were seized from a farm belonging to the the Ampatuan clan near the provincial capital [Reuters]

Officials said the weapons stockpile, some bearing the stamp of the Philippines defence department, were enough to arm a battalion [EPA]